Reproducer for jacoco/jacoco#767

MethodParameterOverwriteTest.java

/*******************************************************************************
 * Copyright (c) 2009, 2018 Mountainminds GmbH & Co. KG and Contributors
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *    Marc R. Hoffmann - initial API and implementation
 *    
 *******************************************************************************/
package org.jacoco.core.internal.instr;

import org.jacoco.core.instr.Instrumenter;
import org.jacoco.core.runtime.IRuntime;
import org.jacoco.core.runtime.RuntimeData;
import org.jacoco.core.runtime.SystemPropertiesRuntime;
import org.jacoco.core.test.TargetLoader;
import org.junit.Test;
import org.objectweb.asm.ClassWriter;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Opcodes;

/**
 * Reproducer for the case where the last local variable slot used by method
 * parameters is overwritten with a two slot variable. This damages the next
 * variable containing the probe array.
 */
public class MethodParameterOverwriteTest {

	@Test
	public void run_original() throws Exception {
		byte[] def = generateMethod();

		TargetLoader loader = new TargetLoader();
		loader.add("Sample", def).newInstance();
	}

	@Test
	public void run_instrumented() throws Exception {
		IRuntime rt = new SystemPropertiesRuntime();
		rt.startup(new RuntimeData());
		Instrumenter instr = new Instrumenter(rt);

		byte[] def = instr.instrument(generateMethod(), "Sample");

		TargetLoader loader = new TargetLoader();
		loader.add("Sample", def).newInstance();
	}

	private byte[] generateMethod() throws Exception {
		final ClassWriter writer = new ClassWriter(0);
		writer.visit(Opcodes.V1_5, Opcodes.ACC_PUBLIC, "Sample", null,
				"java/lang/Object", new String[0]);

		MethodVisitor mv = writer.visitMethod(Opcodes.ACC_PUBLIC, "<init>",
				"()V", null, new String[0]);
		mv.visitCode();
		mv.visitVarInsn(Opcodes.ALOAD, 0);
		mv.visitMethodInsn(Opcodes.INVOKESPECIAL, "java/lang/Object", "<init>",
				"()V", false);

		// Put a long value (2 slots) on position 0, overwriting 'this'
		mv.visitLdcInsn(Long.valueOf(42));
		mv.visitVarInsn(Opcodes.LSTORE, 0);

		mv.visitInsn(Opcodes.RETURN);
		mv.visitMaxs(2, 2);
		mv.visitEnd();

		writer.visitEnd();

		return writer.toByteArray();
	}

}